A resonant sensor including a support, a proof body suspended from the support and having a resonant frequency ωa, an element that measures a force including at least one resonator of resonant frequency ωrn, the force being applied by the proof body, and a mechanical decoupling structure interposed between the proof body and the resonator. The decoupling structure includes a decoupling mass, a first connecting element between the decoupling mass and the proof body, a second connecting element between the decoupling mass and the resonator, the decoupling structure having a main vibration mode whose resonant frequency ωd is such that ωa